At present, a display screen on a market, regardless of passive display or active display, has a light-emitting waveband within a range of 380-780 nm, and short-waveband light having a light-emitting waveband within a range of 380-500 nm is also known as blue ray. Since the blue ray has an injury effect on human eyes and has a great injury to the human eyes particularly when ambient stray light in the night disappears, people generally feel eyestrain after viewing a display screen for long, particularly for people having a habit of night viewing. Therefore, how to effectively prevent the blue ray from injuring the human eyes to protect the human eyes is a technical problem to be urgently solved by those skilled in the art.